Definition. A metric space is a set X together with a function d (called a metric or distance function) which assigns a real number d (x, y) to every pair x, y X satisfying the properties (or axioms): 1  d (x, y) 0 and d (x, y) = 0 x = y, 2  d (x, y) = d (y, x),
Here are some facts and guidelines about formaldehyde in plywood and OSB that can help you when building a chicken coop: 1  Formaldehyde is used in the binders and resins of some manufactured wood products. 2  Offgassing can be an issue with products containing urea-formaldehyde (UF) resins.
PCB. Stands for Printed Circuit Board.. A PCB is a thin board made of fiberglass, composite epoxy, or other laminate material.Conductive pathways are etched or printed onto board, connecting different components on the PCB, such as transistors, resistors, and integrated circuits.PCBs are used in both desktop and laptop computers.onductive pathways are etched or printed onto board, connecting different components on the PCB, such as transistors, resistors, and integrated circuits. PCBs are used in both desktop and laptop computers.